=_Dermophis mexicanus mexicanus_= (Duméril and Bibron).--Natives at Chinajá know caecilians, which they call _dos cabezas_. This species has been taken in Tabasco and northern Chiapas. Its occurrence in southern El Petén is expected. Less likely, the caecilian known to the natives at Chinajá is _Gymnopis oligozona_, which is known from Finca Volcán on the southern slopes of the valley of the Río Cahabón in Alta Verapaz. =_Gastrophryne elegans_= (Boulenger).--This small fossorial frog is known from Piedras Negras (Taylor and Smith, 1945:604), 12 miles east of Yaxha (Stuart, 1934:7), and Tikal (Stuart, 1958:18), all in northern and central El Petén. Two specimens in the collection of the University of Kansas are from 28 kilometers northeast of Campur, Alta Verapaz. Probably the species ranges throughout the forested lowlands of northern Alta Verapaz and El Petén. =_Mabuya brachypoda_= Taylor.--The absence of this widespread lizard in our collections cannot be explained. Probably it occurs in southern El Petén, for it is known in northern and central El Petén and in Alta Verapaz. =_Dendrophidion vinitor_= Smith.--This snake is known from Piedras Negras, El Petén and from various localities in Alta Verapaz; it is an inhabitant of humid forest and should occur in southern El Petén. =_Elaphe triaspis mutabilis_= (Cope).--The subspecies _E. triaspis mutabilis_ is known from Alta Verapaz and _E. triaspis triaspis_ from the Yucatán Peninsula, British Honduras, and Uaxactún in northern El Petén. Because of the much higher degree of resemblance between the faunas of southern El Petén and Alta Verapaz as compared with southern El Petén and Yucatán, _E. triaspis mutabilis_ would be expected to occur in southern El Petén. =_Ninia diademata nietoi_= Burger and Werler.--This snake is known from Tikal and from Alta Verapaz; it is a small cryptophile that probably occurs in southern El Petén. =_Oxyrhophus petola aequifasciatus_= Werner.--This snake, which probably is conspecific with _Oxyrhophus baileyi_ in southern Veracruz, México, is known from Tikal, British Honduras, and Alta Verapaz; it is expected in southern El Petén. =_Pliocercus elapoides salvini_= Müller.--This species is widespread in the Atlantic lowlands of southern México and northern Central America; the subspecies _P. elapoides salvini_ occurs in Alta Verapaz and probably in southern El Petén. =_Rhadinaea decorata decorata_= (Günther).--This is another small cryptophile that is widespread on the Atlantic lowlands from México to Panamá; it definitely is expected at places like Chinajá in southern El Petén.